全文获取类型
收费全文 | 7242篇 |
免费 | 527篇 |
国内免费 | 333篇 |
专业分类
耳鼻咽喉 | 20篇 |
儿科学 | 51篇 |
妇产科学 | 21篇 |
基础医学 | 281篇 |
口腔科学 | 160篇 |
临床医学 | 270篇 |
内科学 | 423篇 |
皮肤病学 | 14篇 |
神经病学 | 189篇 |
特种医学 | 441篇 |
外科学 | 392篇 |
综合类 | 807篇 |
预防医学 | 202篇 |
眼科学 | 11篇 |
药学 | 2744篇 |
1篇 | |
中国医学 | 1987篇 |
肿瘤学 | 88篇 |
出版年
2024年 | 12篇 |
2023年 | 61篇 |
2022年 | 128篇 |
2021年 | 160篇 |
2020年 | 164篇 |
2019年 | 133篇 |
2018年 | 159篇 |
2017年 | 180篇 |
2016年 | 192篇 |
2015年 | 187篇 |
2014年 | 489篇 |
2013年 | 502篇 |
2012年 | 507篇 |
2011年 | 616篇 |
2010年 | 459篇 |
2009年 | 463篇 |
2008年 | 506篇 |
2007年 | 511篇 |
2006年 | 368篇 |
2005年 | 311篇 |
2004年 | 257篇 |
2003年 | 212篇 |
2002年 | 202篇 |
2001年 | 197篇 |
2000年 | 170篇 |
1999年 | 132篇 |
1998年 | 87篇 |
1997年 | 88篇 |
1996年 | 67篇 |
1995年 | 64篇 |
1994年 | 59篇 |
1993年 | 33篇 |
1992年 | 32篇 |
1991年 | 37篇 |
1990年 | 37篇 |
1989年 | 34篇 |
1988年 | 24篇 |
1987年 | 19篇 |
1986年 | 16篇 |
1985年 | 40篇 |
1984年 | 33篇 |
1983年 | 42篇 |
1982年 | 34篇 |
1981年 | 14篇 |
1980年 | 17篇 |
1979年 | 14篇 |
1978年 | 7篇 |
1977年 | 6篇 |
1976年 | 9篇 |
1974年 | 4篇 |
排序方式: 共有8102条查询结果,搜索用时 343 毫秒
1.
2.
Hideyuki Masuda Makoto Kimura Akiko Nishioka Hiroshi Kato Akimichi Morita 《Journal of dermatological science》2019,93(2):109-115
Background
Photosensitizers used for photodynamic therapy (PDT) to treat dermatologic disease are metabolized into mainly protoporphyrin IX (PpIX), which has five absorption wavelength peaks: 410?nm, 510?nm, 545?nm, 580?nm, and 630?nm. Although only red light around 635?nm and blue light around 400?nm are used as light sources for PDT, the efficiency of PDT might be improved by using multiple wavelengths, including those that correspond to the other absorption peaks of PpIX. Furthermore, because the target disease often occurs on the face, a flexible-type light-source unit that can be fitted to the lesion without unnecessarily exposing the mucous membranes, e.g., the eyes, nostrils, and mouth, is preferred.Objective
We investigated the efficacy of a flexible light-emitting diode (LED) unit that emits multiple wavelengths to improve PDT effects.Methods
HaCaT cells were incubated with 5-ALA and subsequently irradiated with either a single wavelength or sequentially with two wavelengths. Cell viability and reactive oxygen species were analyzed. Nude mice were implanted with COLO679 cells by subcutaneous injection into the flank. 5-ALA was subcutaneously injected into the tumor. The tumor was irradiated with 50?J/cm2 (day 0) and assessed daily until day 21.Results
The synergistic PDT effects of dual-wavelength irradiation and reactive oxygen species production were highest with the 405-nm and 505-nm wavelength combination. This dual wavelength combination was also the most effective in vivo.Conclusion
We could therefore conclude that dual-wavelength PDT is an efficient strategy for improving the therapeutic effects of PDT. Using a flexible LED unit is expected to achieve more uniform irradiation of uneven areas. 相似文献3.
4.
《药学学报(英文版)》2020,10(7):1294-1308
A great challenge in multi-targeting drug discovery is to identify drug-like lead compounds with therapeutic advantages over single target inhibitors and drug combinations. Inspired by our previous efforts in designing antitumor evodiamine derivatives, herein selective histone deacetylase 1 (HDAC1) and topoisomerase 2 (TOP2) dual inhibitors were successfully identified, which showed potent in vitro and in vivo antitumor potency. Particularly, compound 30a was orally active and possessed excellent in vivo antitumor activity in the HCT116 xenograft model (TGI = 75.2%, 150 mg/kg, p.o.) without significant toxicity, which was more potent than HDAC inhibitor vorinostat, TOP inhibitor evodiamine and their combination. Taken together, this study highlights the therapeutic advantages of evodiamine-based HDAC1/TOP2 dual inhibitors and provides valuable leads for the development of novel multi-targeting antitumor agents. 相似文献
5.
《Journal of Medical Imaging and Radiation Sciences》2020,51(1):173-181
IntroductionThis study aims to construct learning curves related to the realization of standardized postprocessing by radiographer students and to discuss their exploitation and interest.Materials and MethodsThis study was carried out in 21 French students in their 3rd year of training. Two postprocessing protocols in CT (#1 traumatic shoulder; #2 petrous bone) were repeated 15 times by each student. Each achievement was timed to obtain overall learning curves. The realization accuracy was also assessed for each student at each repetition.ResultsThe learning rates for the two protocols are 63% and 56%, respectively. The number of repetitions to reach the reference time for each protocol is 11 and 12, respectively. In both protocols, the standard deviations are significantly reduced and stabilized during repetitions. The mean accuracy progresses more quickly in protocol #1.DiscussionThe measured learning rates reflect a rapid learning process for each protocol. The analysis of the standard deviations shows that students have reached a homogeneous level. The average times and accuracies measured during the last repetitions show that the group has reached a high level of performance. Building learning curves helps students measure their progress and motivates them.ConclusionObtaining learning curves allows trainers/supervisors to qualify the learning difficulty of a task while motivating students/radiographers. The use of learning curves is inline with the competency-based training paradigm. 相似文献
6.
目的对中药石莼进行生药学研究,为其质量控制提供依据。方法对石莼基原、采收期、采收加工方法进行考证,建立性状、薄层色谱鉴别方法对其进行定性鉴别。结果明确了石莼药材基原、采收期及采收加工方法;所建立的薄层色谱鉴别方法化学成分信息量丰富,专属性强。结论本研究为中药石莼的鉴别、开发利用及质量标准的制订奠定了基础。 相似文献
7.
8.
Lucy Yardley David Papo Adolfo Bronstein Michael Gresty Mark Gardner Nilli Lavie Linda Luxon 《Neuropsychologia》2002,40(4):373-383
The aim of this series of experiments was to determine whether attention is normally required for continuously processing vestibular information concerning orientation, or is required only when orientation is disrupted (eg by vestibular dysfunction or by conflicting visual and vestibular orientation cues). In the first two studies, healthy subjects were passively oscillated, and indicated when they perceived they were passing through their starting position. There was only weak evidence for interference between performance on this 'continuous orientation monitoring task' and on concurrent mental tasks. However, a third study showed that when patients with vestibular imbalance carried out the continuous orientation monitoring task their performance on a concurrent mental arithmetic task was substantially impaired. This dual task interference was correlated with inaccuracy in judging orientation on the continuous orientation monitoring task, which in turn correlated with severity of recent vestibular symptomatology (assessed by questionnaire). In a fourth experiment, disorientation was induced in healthy subjects by rotating the visual field about the line of sight. Bidirectional interference was observed between monitoring orientation (assessed by accuracy in setting a rod to the perceived vertical) and performance of an arithmetic task. Dual task interference was correlated with baseline levels of disorientation induced by the visual field, as indicated by inaccuracy in judging the visual vertical. These findings suggest that monitoring orientation makes significant demands upon cortical processing resources when disorientation is induced, whether the disorientation results from deficient sensory functioning or from ambiguous perceptual information. 相似文献
9.
唇香草中挥发油的理化性质研究 总被引:7,自引:0,他引:7
目的:研究维吾尔药唇香草中挥发油成分的理化性质.方法:采用化学检识、薄层层析法(TLC)、紫外光谱法对唇香草中挥发油成分进行定性分析。结果:唇香草挥发油中含有酚类、醛类、内醇类等不饱和化合物,唇香草中挥发油的薄层层析图谱、紫外光谱图具有明显特征。结论:化学检识、TLC、紫外光谱法可作为控制唇香草内在质量的方法,此方法简便、重现性好。 相似文献
10.
蛋黄磷脂中磷脂酰乙醇胺的薄层扫描测定 总被引:2,自引:1,他引:1
将超临界CO2萃取法得到的蛋黄粉中的磷脂经薄层色谱分离,采用双波长薄层扫描仪对其磷脂酰乙醇胺进行测定。平均回收率为97.67%,RSD为2.31%。 相似文献